Method of manufacturing jack element



April 8, 1969 w. J. STEPPON 3,436,947

METHOD OF MANUFACTURING JACK ELEMENT Original Filed Feb. 7, 1966 Sheetof 2 I6 3 INVENTOR T WI IAM J. ST PPON ATIQRNEE April 8, 1969 w. J.STEPPON METHOD OF MANUFACTURING JACK ELEMENT Sheet Original Filed Feb.7, 1966 INVENTOR WILLIAM J. STEPPON ATTQRNEYS trite tates US. Cl. 72-3394 Claims ABSTRACT OF THE DISCLOSURE A method of manufacturing a channelshaped element having a convex surface defined at an end thereof fromthe material of the element wherein the convex surface is substantiallytangential to the base portion of the channel configuration. Such formedchannel elements are suitable among other uses, for use in scissor jackswherein the convex surface is utilized for bearing purposes.

Cross-references to related applications The present application is adivision of my copending United States application Ser. No. 525,588,filed Feb. 7, 1966, now Patent 3,317,187.

Background of the invention The field of the invention pertains to theformation of channel shaped elements from fiat sheet stock by cuttingand bending operations. The sheet stock is first cut to form a blank ofthe desired configuration, and the blank is then folded in thelongitudinal direction at spaced locations to define a channel shape.Appropriate forms are produced which result in the convex bearingsurface, and

supporting surfaces for the bearing surface are defined on the blankprior to bending.

In the formation of links for jack elements it has been conventional toform the elements by a pair of spaced parallel linkages interconnectedby spacers and fasteners, usually pivot pins. The elements associatedwith the jack load rest are normally pivoted to the load rest. However,in some jack constructions one of the linkages is connected to the loadrest by means of a lost motion arrangement. Lost motion connections areoften expensive to manufacture and assemble. Additionally, as highpressures and forces are imposed upon jack linkages and pivots, failuremay occur where the links are fixed to the load rest, or in the linksitself.

As previously stated, the most common construction for scissor jackelement linkages consists of a pair of elongated elements defining eachlinkage, which are maintained in space parallel relationship by spacers,fasteners or pivot pins. Such linkages are capable of transmitting highforces in the plane of the elements. However, lateral forces imposedupon the linkages will often cause the elements to bend, which maybecome a serious safety hazard,

in that scissor jacks are often employed to elevate vehicles during thechanging of tires.

Summary of the invention The invention pertains to the method of forminga channel shaped element, which may be utilized in a scissors jack, orother environment, wherein an end of the element is provided with aconvex surface substantially tangential to the base portion of theelement. When employed with a scissors jack, an element formed in accordWith the method of the invention utilizes the convex end surface as ahearing which slidably engages the underside of the jack load rest.

The channel shaped element in accord with the invention is formed from aplanar blank wherein the end of the blank is shaped While in its planerconfiguration. After the desired configuration of the blank is achieved,such as by a stamping operation, the blank is bent into a crosssectional channel configuration. After the channel configuration isformed the element is bent adjacent the end to produce the convexbearing surface.

The arcuate convex portion of the element is formed from the baseportion of the channel configuration and cooperates with locating andsupporting surfaces or notches defined upon the leg portions of thechannel configuration. In this manner the convex portion is tangentialto the base portion, when viewed in the longitudinal direction, and theconvex portion is supported adjacent its free end upon the element legportions. The convex portion may be so formed as to directly engage thelocating notches upon the leg portions, and a Welding operation or othertype connection is not necessary to insure engagement of the convexportion with the leg portions.

Brief description of the drawing While the method of manufacturing achannel shaped element in accord with the invention is not limited tothe use of forming jack elements or links, for the purpose ofillustration and comprehension the invention will be described in thisenvironment. Thus, the purposes of the invention arising from thedetails and relationships of the components of an embodiment thereofconstructed in accord with the method of the invention will be apparentfrom the following description and accompanying drawings wherein:

FIG. 1 is an elevational, perspective view of a scissors jack in accordwith the invention shown in the partially elevated position, portions ofthe structure being cut away for purposes of illustration,

FIG. 2 is an elevational view of a scissors jack in accord with theinvention when fully retracted, a portion of the load rest mountinglinkage being cut away to illustrate the relaionship of the load rest tothe pivot stud,

FIG. 3 is an enlarged, detail, elevational, sectional view of the loadrest and associated links during elevation in accord with the invention,

FIG. 4 is a side elevational view of the formed channel jack link inaccord with the invention,

FIG. 5 is a plan view of the link of FIG. 4,

FIGS. 6, 7 and 8 are elevational, sectional views taken through the linkof FIG. 4 along sections VIVI, VII VII, and VIII-VIII, respectively,

FIG. 9 is a plan View of the end of the blank from which thechannel-shaped link of FIG. 4 may be formed, prior to folding of theblank, and

FIG. 10 is an elevational, detail view of a modification of pivot pinreceiving opening and throat defined in a yoke portion.

Description of the preferred embodiment In order to appreciate themanner in which'the convex surface of a link formed in accord with themethod of the invention may be practically utilized, the link element isshown and described as incorporated into a scissors jack of the typeillustrated. The jack includes a base preferably formed of a sheetmaterial fabricated by a stamp ing and bending operation. The base 10includes a substantially horizontally disposed portion 12 from whichdepends vertically extending spaced wall portions 14. A pair of spaced,parallel pivot pins 16 and 18 are mounted on the base wall portions 14and extend thereacross. The pivot pin 16 serves as the support for thejack link and the pivot pin 18 supports the jack link 22. The link 20and the link 22 each consists of a pair of spaced, parallel, stampedmetal elements 24 and 26, respectively, having a lower end through whichthe associated pivot pin extends. The pivot pins are each provided witha sleeve spacer 28 circumscribing the central region of the pivot pin tomaintain the spacing and separation of the elements of a common link. Asis the usual practice, the lower ends of the link elements of the links20 and 22 are each provided with meshing gear teeth 30, whereby pivotingof the links with respect to the base 10 is controlled, and the links 20and 22 will pivot in an equal manner relative to the base duringoperation of the jack.

The jack also includes a link 32 and a link 34, each having an upper endand a lower end. The link 32 consists of a pair of stamped, parallelelements 36 and the link 34 is of a channel transverse cross-sectionalconfiguration which will be more fully described later. The lower end ofthe link 34 is formed as a yoke defined by a pair of spaced linkportions 38.

The upper ends of the link elements 24 are pivotally mounted upon pivots40 extending from opposite ends of a block 42 interposed between thelink elements, FIG. 1. In FIG. 1 only one of the pivots 40 is shown, inthat the other extends away from the viewer. The lower end of each ofthe link elements 36 is provided with a hole through which a pivot 40extends, and the pivots 40 are swaged at 44 to maintain the linkelements 24 and 36 thereon in a pivotal manner.

The link elements 26 are pivotally mounted upon pivots 46 extending fromthe end surfaces 48 of a block 50. Also, the yoke portions 38 of thelink 34 are disposed adjacent the block surfaces 48 and are formed withan opening for receiving the pivots 46. In this manner it will beappreciated that the upper end of the link 20 is pivotally connected tothe lower end of the link 32, and the upper end of the link 22 isconnected to the lower end of the link 34.

The block 50 is provided with a bore through which the cylindrical shank52 of an adjusting screw 54 extends. The adjusting screw 54 has ahexagonal head 56 defined on the outer end thereof, and a thrust bearingis interposed between the head 56 and the block 50. The thrust bearing,preferably, consists of a pair of steel washers 58 having a nylon washer60 inserted therebetween. The adjusting screw shank portion 52 may bestaked, or otherwise provided with means disposed adjacent the inside ofblock 50, to prevent axial movement of the adjusting screw relative tothe block but permit rotationof the screw relative thereto. The block 42includes a threaded bore 62 through which the threaded portion of thescrew shaft 54 extends.

The link elements 36 pass on each side of the link 34 and a pivot stud64 extends through holes in the link elements 36 and the link 34 topivotally connect the links 32 and 34 together.

The upper end of the link 32 is provided with a pivot pin 66 upon whichthe channel-shaped load rest 68 is pivotally mounted. The load rest 68includes a base portion 70 from which depends side portions 72 which arein spaced, parallel relation to each other. The load rest base portion70 is of a nonplanar, concave configuration, as will be apparent fromFIG. 3, and includes a convex undersurface 74 adapted to be slidinglyengaged by the upper end of the link 34. The load rest base portion 70is of a configuration wherein when the ends of the load rest aresubstantially horizontally related, the lowermost portion of the baseportion underside as represented at 76 occurs well toward the pivot pin66 with respect to the right load rest end, FIG. 3. The purpose of theconvex configuration of the load rest surface 74 is to increase theelevation of the load rest base portion as the jack approaches itsmaximum elevation, and this operation will be more fully described laterin the specification.

With some vehicles it is desirable that a frame engaging saddle beafiixed to the load rest, and such a saddle is shown in dotted lines inFIG. 3. The saddle 78 may be of sheet material and includes a groove 80in which a rib or projection defined on the underside of the vehiclebody may be received.

The link 34 is of a channel-shaped, transverse cross section including abase portion 82 from which depends lateral side portions 84 terminatingin side edges 86. A longitudinally extending depression is, preferably,formed in the base portion 82 for increasing the resistance of the linkto bending. The link side portions 84 are each formed with a hole 83intermediate the ends of the link for receiving the pivot stud 64.Adjacent each of the holes 88 defined in the side portions, the sideportions are deformed outwardly at 90 to define outer edges which serveto space the link elements 36 when the jack is assembled.

The lower end of the link 34, as previously mentioned, is defined by ayoke formed from extensions of the side portions 84 to form yokeportions 38 which are outwardly related to the side portions 84. Each ofthe yoke portions 3-8 is formed with an end edge 92 and a lower edge 94which lies on the same plane as the side portion edges 86. An opening 96is defined in each of the yoke portions 38 and is preferably of acircular configuration capable of receiving a pivot 46 of the block 50.A slot, or throat 98, is defined in the yoke portions 38 intersectingthe end edge 92. The throat 98 is of a normal transverse dimensioncapable of slidably receiving the pivots 46- whereby the yoke may beassembled to the block 50. After the yoke side portions 38 have beenslipped over the pivots 46, the yoke is deformed by swaging, or similaroperation, in a direction indicated by the arrows 100, FIG. 4, to reducethe transverse dimension of the throat 98 to such a dimension as toprevent the pivots 46 from leaving the openings 96 and entering into thethroat whereby the yoke could be removed from the pivots. After the yokeportions 38 have been deformed, the yoke will be permanently connectedto the pivots 46, yet a pivot interconnection between the link 34 andthe block 50 will be maintained as the pivots will be rotatably receivedwithin the circular openings 96.

As the upper end of the link 34 is adapted to slidingly engageundersurface 74 of the load rest base portion 70, the link upper end isprovided with a convex bearing surface 102 which is capable of engagingthe load rest undersurface without galling or otherwise damaging theload rest. To provide the convex bearing surface at the upper end of thelink 34, a portion of the link member base portion 82 is arcuately bentfrom the general plane of the base portion in the direction of the sideportions 84. The side portions 84 are each formed with a longitudinallyextending shoulder 104 immediately adjacent their ends 106 which issubstantially parallel to the general plane of the base portion, and asurface 108 is formed in each side portion which intersects the shoulder104. The surface 108 is perpendicularly disposed to the longitudinallength of the link, and is located inwardly of the associated end 106 ofthe side portion a distance substantially corresponding to the thicknessof the portion of the base portion which is bent toward the sideportions. The end 110 of the bent base portion 112 engages the shoulders104, and the underside thereof engages the surfaces 108 whereby therelationship which will be apparent from FIGS. 3, 4 and 8 is produced.It

will be noted that portion 112 is of a Width adjacent its end 110 equalto the normal width of the link 34. In this manner the convex portion112 is firmly supported and will maintain its arcuate form to definebearing surface 102 even under heavy loads.

A manner of forming the upper end of the link member 34 is illustratedin FIG. 9. The link 34 may be formed from flat sheet steel which isfolded to the channel-shaped configuration of the link. When the link 34is formed in this manner, the arcuate end thereof is formed as shown inFIG. 9 prior to the link being bent into the channel shape. Prior toforming the end of the link, the link blank 114 would have a rectangularend configuration as represented by the dotted lines 116, FIG. 9. Theblank 114 is placed within a die and is notched adjacent the end on bothsides of the blank central region to define a pair of notches 118. Thenotches 118 form parallel surfaces 120 which define the maximum width ofthe tongue 122. Surfaces 124 define the minimum width of the tongue, andthe surfaces 120 and 124 on each side of the tongue are interconnectedby an inclined surface 126. Arcuately formed surfaces 128 intersect thesurfaces 124 and intersect the surfaces 108 which are perpendicularlydisposed to the longitudinal axis of the blank. The shoulder surfaces104 are disposed parallel to each other and to the longitudinal axis ofthe blank. The ends of the side portions are defined by the surfaces106, as described above, and the end of the tongue constitutes end 110.After the blank is shaped as shown in FIG. 9, the blank is folded alonglongitudinally extending dotted lines 130 to the channel configuration,whereby the side portions 84 are disposed in a substantially parallelrelation on a common side of the general plane of the central baseportion 82. The tongue 122, which forms base portion 112, is then benttoward the shoulders 104 to engage the shoulders 104 and surfaces 108,as shown in FIGS. 3, 4 and 8. The formation of the convex link end doesnot require welding or other secondary operations after the portion 112is bent into engagement with the shoulders 104 and surfaces 108. As willbe apparent from FIGS. 5 and 8, the width between the surfaces 120corresponds to the width of the link end and a clean appearing andeffective convex bearing surface is provided which is capable ofwithstanding the loads which will be imposed thereon during ordinaryservice.

Extension and retraction of the jack is produced by rotating the screw54 by means of a wrench applied to the hexagonal head 56. Normally, thethreads of the screw will be of a right hand whereby clockwise rotationof the screw draws the blocks 42 and 50 toward each other to extend thejack and raise the load rest 68 relative to the base 10. When the screw54 is rotated the maximum degree in the counterclockwise direction, thejack will assume the retracted and compact relationship shown in FIG. 2.In FIG. 2 a portion of a link element 36 is broken away to illustratethe presence of the notch 132 defined in each of the side portions 72 ofthe load rest which provides clearance for the pivot stud 64 and theoutwardly formed spacer deformations 90 formed on the link 34 adjacentthe pivot stud holes 88.

As the jack is extended from the position shown in FIG. 2 toward theextended position, it will be appreciated that the link 34 will sliderelative to the load rest 68. In the fully retracted position of FIG. 2,the convex end of the link 34 extends substantially beyond the load restand as the jack is extended, the load rest undersurface 74 will slidealong the link base portion 82. As the jack approaches its maximumextension, the arcuate, convex bearing surface 102 will engage the loadrest undersurface 74, as shown in FIG. 3. Preferably, the undersurface74 is lubricated to minimize the friction between the load restundersurface and the convex bearing surface. Further extension of thejack from the position shown in FIG. 3 causes the convex bearing surface102 to approach and ride on the downwardly depressed portion 76 of theload rest base portion as the convex bearing surface approaches thepivot pin 66. The downwardly depressed portion 76 will cause anincreased counterclockwise pivoting of the load rest 68 about the pivotpin 66, FIG. 3, in an upward manner even though little relative slidingmovement between the convex bearing surface and the load restundersurface takes place. Thus, the presence of the downwardly defiectedload rest portion 76 permits an extra elevation of the load rest 68which would not be possible if the load rest base portion were of aplanar configuration.

In FIG. 10 a modification of the formation of the pin receiving openingand throat defined in the yoke portions 38 of the link 34 is shown. InFIG. 10 the pivot pin circular opening 134 is located with respect tothe associated yoke portions at the same location as the embodiment ofFIG. 4. However, the pin receiving slot or throat 136 defined by thesurfaces 138 intersects the lower edge 94' of the yoke portions 38',rather than the end 92 thereof, as in the embodiment of FIG. 4. The yokeemployed in the embodiment of FIG. 10 is placed on the pivots 46 in thesame manner as previously described and after assembly to the pivots 46,the yoke portions 38' are subjected to a force as indicated by the arrowto reduce the dimension of the space separating the throat surfaces 138and, thus, retain pivots 46 within the circular openings 134.

It will be appreciated that in accord with the invention the link 34 hashigh strength characteristics. By utilizing the channel-shapedconfiguration, high resistance to bending of the link 34 is achievedeven though the link may be formed of #7 gauge hot rolled sheet steel.The yoke construction at one end of the link permits the link to bereadily afiixed to the pivots of the block 50 and the pivot receivingopenings and throat defined therein simplify assembly. The constructionof the integral convex bearing surface 102 reduces fabrication costs, inthat extra material is not required and, yet, an effective nongalling,convex bearing surface is achieved. The support of the bearing surfaceon the shoulders 104 and surfaces 108 adequately supports the convexbearing surface defining portion 112, and scissor jacks constructed inaccord with the invention have continued to operate successfully wellbeyond the required number of cycles during life determination tests.

It is appreciated that various modifications to the disclosed embodimentmay be apparent to those skilled in the art without departing from thespirit and scope thereof, and it is intended that the invention belimited only by the following claims.

I claim:

1. The method of forming an elongated element having a transverse crosssection of a channel configuration including a central base portion,side leg portions and a convex bearing surface adjacent an end from anelongated fiat blank having a longitudinal axis, a central portion, sideportions disposed on each lateral side of said central portion and anend, comprising the steps of notching the blank side portions adjacentto and intersecting the end thereof on each lateral side of thelongitudinal axis of the blank to define a centrally disposed cantileversupported tongue having a longitudinal length parallel to the blank axisand an end transversely related to the tongue length, and defining alongitudinally extending projection upon each blank side portion on eachside of said tongue, said tongue having a greater longitudinal lengththan said projections, forming a shoulder facing said tongue andtransversely disposed to the end of said tongue in each of saidprojections and at an axial location on said blank intermediate thetongue end and the axial depth of said notches, longitudinally foldingsaid blank at the axial regions of association of said side portionswith said central portion whereby said side portions are disposed on acommon side of said central portion and are spaced apart a distance lessthan the transverse width of said tongue adjacent the end thereof, andbending said tongue in an arcuate convex manner in the direction of saidfolded side portions to engage the tongue end with said side portionshoulders.

2. A method of forming an elongated element as in claim 1 wherein theend of said tongue is formed perpendicular to the blank longitudinalaxis and said shoulders are formed parallel to the blank longitudinalaxis.

3. The method of forming an elongated element as in claim 2 comprisingthe step of forming a locating surface on each of said projectionsperpendicular to the axis of said blank and intersecting said shoulderformed on the associated projection whereby said locating surfaceslocate the tongue end on said shoulders when bent into engagementtherewith.

4. The method of forming an elongated element as in claim 1 comprisingthe step of folding said blank at the axial regions of association ofsaid side portions with said central portion such that said sideportions are substantially parallel to each other.

References Cited UNITED STATES PATENTS Re 16,806 12/1927 Reeves 254-1262,765,525 10/1956 ONeill 113-116 FOREIGN PATENTS 588,576 5/1925 France.CHARLES W. LANHAM, Primary Examiner.

E. M. COMBS, Assistant Examiner.

